Heating element



7 Aug. 14, 1923. 7 1,464,703

L. J FULLER HEATING ELEMENT Filed Feb. 2, 1922 INVENT R A TTOR NE YS Patented Aug. 14, 192 3.

' 1,464,703 I v UNITED STATES PATENT "OFFICE.

"- L'ouIs JAMES. ruLtna, or BnooKLYmnnw YORK, ASSIGNOR TO 'DUPABQUET, HUOTI & monnusn COMPANY, or N W YORK, N. Y., A CORPORATION or NEW YORK.

HEATING- ELEMENT.

Application filed February 2, 1922. Serial nogssasw.

Toall whom it may, concern."

Be it known that I, LOUI$ J AMES FULLER,

' a citizen of the United States, residing at Brooklyn, in the county of Kings, State of New York, have invented certain new and useful Improvements in Heating Elements;

and I do hereby declare the followingto be the art to which it appertainsto make and use the same. I

My invention is an. improvement in electric heatingelements, and relates particu larly to elements of the type designed to be submerged in a liquid to be heated. Heating elements bf this type are very susceptible to overheating, and consequent injury, when for any reason the liquid falls to a int such that the heatin or-resistance coils of the element are no Ionger submerged. In

, order that the heating element may function properly, the coils of .the resistance wire -must be thoroughly insulated from each other, and to insure complete and permanent insulation, the wire is usually embedded in cement. The heating element is rapidly cooled through convection, the surrounding liquid carrying awaythe heat, and there is no danger of overheating, so long as the element is submerged. When, however, for any reason, as for instance neglect of the attendant, the liquid falls below the to of the element, so that a portion thereot is exposed to the air, the element rapidly overheats, because the heat is, no longer carried away, and injury results, the heating wire fusing at some. point in the exposed portion, and breaking the circuit. The wire is usually in coils, and so arranged in the element, that portions of a number of coils will simultaneously emergewhen the liquid fallsbelow the top of the heater. It is inthese portions that the break occurs and it is impossible to the vessel, as for instance a coffee urn, is out of commission for an extended period.

In the present invention, I segregate an independently insulated portion of the heating or resistance wire, and arrange it in such relation with respect to the remainder, that end to the succeeding 'rection, and-across to the su such auxiliary portion will first emerge when the liquid falls below the safety level,

easily detached and removed, to be replaced by another, thereby to permit the heater to function with as little loss of time as possia full, clear, and exact description-of the 1nbl vention, such as will enable others skilled in Figure, 4 is a diagrammatic \view of the plan view of the wiring,

Figure 5 is a perspective view of one of the insulating-tubes or casings.

In the present embodiment of the invention, the improved heating-element-or unit,

comprises an annular cup-shaped casing 1,

having at its bottom a transverse web 2, which has a central threaded perforation 3,

- axial' to the casing l. The web 2 is at the open end of the casing, and the casing has at the said end an external. annular flange 4, which is adapted to fit against the wall 5 of of a coifeethe vessel 6, within which the element? is arranged, the said vessel 6 being in the present instance, a cofiee urn, having the usual liquid gauge 7, and safety valve 8. r

The heating or resistance wire indicated at 9, is wound into a plurality of coils, and the individual coils are arran ed within the cylindrical bores of insulating tubes 10.

These tubes are placed within the casing 1, I

in the manner shown in Figure 3, there being a plurality of pairs-of tubes, the members of the pair lying radial to the casing.

, The coils are so arranged, in the tubes, that the wire is continuous from a binding post 11 to which one terminal of the wire is connected, to a binding post 12 to which the other terminal ofthe wire is connected.

Referring to Figure 3,-it will be seen that the wire passes from the terminal 11 through the adjacent tube 10, across at the opposite tube in the outermost series, through said tube in the op 'te diing tube of the series. This'prooedui'e is continued about the tubes of the outermost series, until the wire from the last tube of the said seend of the casing, filling the space between ran 'thetubes, and filling the space within the tubes about the coils. The cement also makes a plug 14 which closes the open end of the casing, and through which the terminals 11 and 12 extend.

In making a heater of known capacity, as for instance 2 k. w., I will make the coils in the tubes 10 of a capacity of 1950 watts. The remaining 50 watts capacity, I would provide for by an auxiliary coil 16, which is disposed at a higher level than the main portion of the heating element, and which is segregated therefrom, and independently insulated. In the present instance, I arthis auxiliary coil within a casing 17 of t e same material as the casing 1, one end of the auxiliary casing being closed, and the other end open, and at the said open end, I provide a threaded portion 18 for engaging the threaded opening 3 of the casing 1. The casing 17 has a hexagonal flange 19, for convenience in turning the same, and within the casing, and arranged axially thereof there is a tube 20 of insulating material, as

for instance porcelain. The wire 21 passes through this tube, and is coiled around one end of the same to form the coil 16, after which the end of the wire passes out alongside the porcelain tube 20, and is connected with a binding post 22. The opposite end of the wire 21 is connected with the terminal 12 before mentioned. The space between the tube 20 and the casing 17 is filled with cement, and the casing, and the tube 20, are of such length, that when the casing is screwed into the opening 3, the coil 16 will be at a higher level, than the coils of the wire 9. The casing 1 is arranged within the vessel 6, extending through an opening in the bottom thereof, with the flange 4 abutting the under face of the bottom, and it is secured thereto in any suitable or desired manner., When so arranged, the coil 16 is at higher lever than any other portion of the wire 9, and when the liquid in the vessel falls below the safety line, the coil 16 will be first to emerge from the liquid. Hence this portion of the wire will be the first to overheat the fuse. When this happens, the wire 21 is disconnected from the terminals 12 and 22, and the casing 17 is removed, to be replaced by another, when the heating element is again in condition for use. The

terminals 12 and 22 are connected with the usual circuit, and the circuit is controlled by a switch indicated at 23.

The casing 17, containing the auxiliary coil 16 may be considered as a renewable cartridge which serves to protect the main part of the heating element and which may readily be replaced without injuring or in any way disturbing the main, portion of the element.

I claim:

1. A heating element comprising a main portion consisting'of a plurality of coils of resistance wire and an auxiliary portion comprising a single coil of resistance wire, said coil being segregated and independently insulated and arranged at a different level from the coils of the main portion of the heating element, whereby said coil may serve to prevent the resistance wire in the main portion of the unit from overheating.

2. A heating element comprising a main portion consisting of a plurality of coils of resistance wire and an auxiliary portion comprising a single coil of resistance wire, said coil being segregated and independently insulated and arranged at a higher level from the coils of the main portion of the heating element, whereby said coil may serve to prevent the resistance wire in the main portion of the unit from overheating.

3. A heating element comprising a main portion consisting of a plurality of coils of resistance wire connected in series and insulated from each, other, and an auxiliary coil arranged at a higher level than the coils in said main portion of the heating element, and means for disconnecting said auxiliary coil from the remaining coils.

4. A heating element comprising a resistance'wire arranged in coils, one of said coils being segregated, a casing for said coil and a casing for the other coils with which said first named casing is detachably connected.

5. A heating element comprising a resistance wire arranged in coils, one of said coils being segregated, a casing for said coil, and a casing for the other coils with which said first named casing is detachably connected, said last named casing being of a length to project said coil beyond the other coils for the purpose specified.

6. A heating element of the character specified, comprising an annular casing opn at one end, a plurality of series connected heating coils within the casing insulated from each other and from the casing, an in.-

dependently insulated coil in series with the other coils, and-means for supporting said last named coil at a different level from the other coils whereby said last-named coil may serve to prevent the remaining coils from overheating, said last-named coil being adjustably connected to the remaining coils.

7. A heating element of the character specified, comprising an annular casing open at one end, a plurality of series connected heating coils within the casing insulated from each other and from the casing, an independently insulated coil in series with the other coils, and means for detachably connecting said last narned coil to the casing to support said coil at a difierent'level from the other coils. Y p 4 8. A heating element of the, character specified, comprising an annular casing op'en at one end, and having a transverse web at the said end provided with a central opening, a plurality of series connected heating coils within the casing insulated from each other and from the casing, a casing detachably connected with the web andextending I through the opening, and a coil of resistance wire in the said casing in series with the other coils, said casing being of a length to extend the coilbeyond the other coils. S

9, In a heating element of the character specified, an annular casing open at one end, a plurality of insulating tubes within the casing, each tube carrying a heating coil, said coils being connected in series, each of the tubes having an external rectangular crolss-section, and being cored to receive'the co1 a In testimony whereof I afiix my signature.

LOUIS JAMES FULLER. 

